عَنْ أَبِي سَعِيدٍ رَضِيَ اللَّهُ عَنْهُ قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ الْقُلُوبُ أَرْبَعَةٌ قَلْبٌ أَجْرَدُ فِيهِ مِثْلُ السِّرَاجِ يُزْهِرُ وَقَلْبٌ أَغْلَفُ مَرْبُوطٌ عَلَى غِلَافِهِ وَقَلْبٌ مَنْكُوسٌ وَقَلْبٌ مُصْفَحٌ فَأَمَّا الْقَلْبُ الْأَجْرَدُ فَقَلْبُ الْمُؤْمِنِ سِرَاجُهُ فِيهِ نُورُهُ وَأَمَّا الْقَلْبُ الْأَغْلَفُ فَقَلْبُ الْكَافِرِ وَأَمَّا الْقَلْبُ الْمَنْكُوسُ فَقَلْبُ الْمُنَافِقِ عَرَفَ ثُمَّ أَنْكَرَ وَأَمَّا الْقَلْبُ الْمُصْفَحُ فَقَلْبٌ فِيهِ إِيمَانٌ وَنِفَاقٌ فَمَثَلُ الْإِيمَانِ فِيهِ كَمَثَلِ الْبَقْلَةِ يَمُدُّهَا الْمَاءُ الطَّيِّبُ وَمَثَلُ النِّفَاقِ فِيهِ كَمَثَلِ الْقُرْحَةِ يَمُدُّهَا الْقَيْحُ وَالدَّمُ فَأَيُّ الْمَدَّتَيْنِ غَلَبَتِ الْأُخْرَى غَلَبَتْ عَلَيْهِ
It is narrated from Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: Hearts are of four types: (1) A pure and clean heart, which is bright like a lamp; (2) A heart enclosed in a covering, from which the covering can never be removed; (3) An inverted heart; and (4) A double-faced heart. Their details are as follows: The pure heart refers to the heart of a believer, its lamp is its light; the heart enclosed in a covering belongs to a disbeliever; the inverted heart is that of a hypocrite who, after attaining the knowledge of truth, denies it; and the double-faced heart is the one in which there is both faith and hypocrisy. In it, the example of faith is like that of a green plant, which is nourished by pure water, and the example of hypocrisy is like that of a boil, which grows due to pus and blood. Whichever of the two increases more, that one prevails.